Before spending a lone season with the Aggies, where he served on the same coaching staff with Kingsbury, Wallerstedt spent the previous four with Air Force, where he served as defensive coordinator under Troy Calhoun. He has almost a quarter century of coaching experience, which also includes defensive coordinator positions at North Alabama (2003) and Wyoming (1997-2002) and a stint as special teams coordinator and linebackers coach at Kansas State (2006-07).

Texas Tech has not officially announced any hires since Kingsbury took the head-coaching job on Dec. 12. A Tech spokesman said last week that no announcements will be made until the staff is complete.

Including Kingsbury, the average age of the staff is 35 with six members being 33 or younger.

Wallerstedt has coached in seven bowl games, including Texas A&M’s Cotton Bowl rout of Oklahoma earlier this month. The Aggies this season ranked ninth in the 14-team Southeastern Conference in total defense at 390.2 yards per game.

Tech finished 38th in total defense this season (367.1) under Art Kaufman, a major improvement from its 114th ranking in each of the previous two seasons. The Red Raiders’ entire 2012 defensive staff, including Kaufman, went with former coach Tommy Tuberville to Cincinnati.

Wallerstedt is a native of Manhattan, Kan., and played linebacker at Kansas State from 1984 through 1987. He led the Wildcats in tackles his junior and senior years and was an an honorable mention All-American in 1987.

He then started his coaching career as a Kansas State student assistant in 1988. He was an Arizona State graduate assistant in 1989 and 1990 and made his next stops at Fort Hays State and Emporia State before going to Wyoming.